Encephalitis

Encephalitis is inflammation of the substance of the brain itself. It is uncommon, but it belongs to that group of conditions in which everything is decided within hours: the brain sits inside a rigid box of bone, it has nowhere to swell into, and the time between the start of the illness and irreversible damage is shorter than most people imagine. Anyone can develop it, though the most severe cases occur in small children, in older people and in those whose immune defences are weakened by treatment or by another illness. The good news is that starting treatment early changes the outcome completely, so this text has a single purpose: to teach the reader to recognise encephalitis soon enough not to be too late.

What happens to the brain

Inflammation means swelling and an influx of immune cells into a place with no spare room for them. Nerve cells stop working properly and some of them die. The whole picture follows from that: since the brain governs consciousness, speech, movement, behaviour and memory, any of those functions can fail, and from which one fails the doctor works out which area is involved.

There are essentially two causes of the inflammation. The first is an infection that has reached the brain: usually a virus, far less often a bacterium, a fungus or a parasite. The second is a mistake by the person's own immune system, which starts attacking nerve tissue having taken it for foreign. The second sounds unfamiliar, but it is less rare than it seems and is treated in an entirely different way, so telling one from the other is the doctors' main task in the first few days.

And the point that always worries relatives: encephalitis itself does not pass from person to person. The infections that lead to it — cold sores, chickenpox, measles — are catching, but the overwhelming majority of people who pick them up have the ordinary illness and it never reaches the brain.

How it starts and what it looks like

The treacherous thing about encephalitis is that it starts unremarkably. The first hours or days look like a cold or flu: a high temperature, headache, aching muscles and joints, nausea, sometimes a rash. Nothing to put anybody on alert.

The turning point comes when the brain becomes involved. That can take a few hours, or it can stretch over days and weeks, and in the autoimmune form even months. Anything that changes the person should raise the alarm:

• confusion, not knowing the time or the place;
• unusual drowsiness that is hard to rouse them from, or, conversely, marked agitation;
• a seizure, particularly a first one;
• a sharp change in behaviour and character: aggression, fear, actions that make no sense, speech that is beside the point;
• difficulty speaking: hunting for words, muddling them, or slurring;
• weakness in an arm or a leg, a droop on one side of the face, loss of sensation;
• hallucinations — seeing or hearing things that are not there;
• uncontrolled eye movements, double vision, loss of part of the visual field;
• loss of consciousness.

Signs of inflammation of the linings of the brain often accompany all this: an unbearable headache, discomfort in bright light, a stiff neck that will not let the chin reach the chest, and a rash that does not fade when a clear glass is pressed against it.

In babies the picture is different and harder to read: refusing feeds, an unusual high-pitched monotonous cry, floppiness or a distress that does not settle when held, a bulging soft spot on the head, convulsions.

When to call an ambulance

Call an ambulance immediately (in Spain, Italy, Portugal, Poland and Ukraine the single European number 112 is in use) if someone, with or without a temperature, develops confusion, seizures, strange behaviour, difficulty speaking, weakness in the limbs, heavy drowsiness or loss of consciousness. The same applies to a severe headache combined with a stiff neck and discomfort in the light, and to any rash that does not fade under glass. In a child, seizures, unusual floppiness, continuous crying and a bulging soft spot all warrant the call.

Do not wait until morning, do not try bringing the temperature down to see what happens, and do not drive the patient yourself. While the ambulance is on its way, lay the person on their side so that vomiting or a seizure cannot block their breathing, and give them nothing to eat or drink. Being wrong and calling unnecessarily is nothing to be embarrassed about here: the cost of waiting bears no comparison to the cost of one extra call.

Where it comes from

The cause is not always established, and treatment begins regardless. When a cause is found, it is usually one of the following.

The herpes simplex virus. The commonest cause in people with no particular risk factors. It is the same virus that produces cold sores and that lives in most adults' bodies. In the rarest of cases it travels up the nerves to the brain, and then the illness is severe. This is exactly why the antiviral drug is started at once, without waiting for test results.

The chickenpox and shingles virus. The same agent that causes chickenpox in childhood and shingles in adult life.

The measles, mumps and rubella viruses. These reappear wherever vaccination coverage falls.

Viruses carried by animals and insects. Tick-borne encephalitis in wooded parts of Europe and Asia, Japanese encephalitis in a number of Asian countries, and rabies after an animal bite or lick. One thing about rabies is essential: once symptoms appear it cannot be cured, yet it is entirely preventable if the wound is washed at once and vaccination is sought. Any bite from an unfamiliar or wild animal means seeking care the same day rather than keeping an eye on the wound.

Bacteria, fungi and parasites. An uncommon cause, though in people with weakened immunity it is looked for with particular care.

The immune system itself. This is worth dwelling on, because it is the version most often missed. The immune system can start producing antibodies against receptors on nerve cells. The illness then begins not with fever but through the mind: a person, usually young, changes in character within a few weeks, and anxiety, sleeplessness, strange ideas and hallucinations appear. They are frequently taken for a first psychiatric episode and treated for the wrong thing, and then come seizures, involuntary movements of the face and hands, and disturbances of heart rhythm and breathing. In a proportion of cases, most often in young women, the trigger is a small ovarian tumour, and once it is removed alongside treatment that damps down the immune attack, people recover. That is why a psychosis that has appeared recently and quickly, all the more so with seizures, fever or unusual movements, is a reason to be assessed by a neurologist and not by a psychiatrist alone.

Telling it apart from its look-alikes

The symptoms of encephalitis are not its own private property: a stroke, a brain tumour or abscess, severe poisoning, a sharp drop in blood sugar or meningitis can all look the same. The investigations are therefore arranged so as to rule those out quickly.

• Brain imaging. A CT scan comes first because it is fast and immediately excludes a bleed. An MRI scan tells more: in herpes encephalitis it often shows characteristic changes in the temporal lobes.
• Lumbar puncture. The key test. A fine needle takes a small amount of fluid from the space around the spinal cord, below the level at which the cord ends, and the sample is examined for cells, protein and traces of the organism. This is where the virus is found most often. It is done under local anaesthetic, takes minutes, and, contrary to the usual fear, the spinal cord is not touched.
• Electroencephalogram. Sensors on the head pick up the brain's electrical activity. It helps to locate the affected area and to detect seizure activity that is invisible from the outside.
• Blood and other fluid tests for the organism and for antibodies and, where an autoimmune cause is suspected, specific antibody tests against nerve tissue and a search for a hidden tumour.

Treatment in hospital

Encephalitis is treated only as an inpatient, often in an intensive care unit, and the stay may run from a few days to several months. Treatment proceeds along two lines at once: dealing with the cause and supporting the body.

The antiviral drug is given into a vein without waiting for results, over a course of two to three weeks: if a herpes origin is confirmed, decisive time will have been gained, and if not, little has been lost. In the autoimmune form, high doses of hormonal anti-inflammatory drugs are used, along with immunoglobulin infusions and plasma exchange, a procedure that removes from the blood the antibodies attacking the brain; if a tumour is found, it is removed. Where the cause is bacterial or fungal, antibiotics or antifungal drugs are prescribed.

Supportive treatment matters no less: fluids by drip, drugs to bring down fever and relieve pain, anticonvulsants, medicines to reduce the pressure inside the skull, oxygen by mask and, if needed, mechanical ventilation and sedation. In rare cases, when the pressure inside the skull will not come down with medication, a surgeon temporarily removes a section of bone to give the brain room.

What is left afterwards

The outcome depends heavily on the cause and on how quickly treatment began. Some people recover fully, though recovery takes months. In herpes encephalitis the outlook is more serious: even with treatment roughly one person in five dies, and a considerable share of survivors are left with lasting difficulties. That is precisely why this text gives so much space to early recognition.

What most often remains is:

• memory problems, particularly for recent events;
• changes in character and behaviour, short temper, the loss of a previous restraint;
• difficulty with speech and with understanding words;
• repeated seizures, in other words epilepsy;
• trouble swallowing;
• problems with balance, coordination and movement;
• anxiety, depression, swings of mood;
• severe fatigue, which is the slowest of all to lift.

Rehabilitation addresses all of this, and it starts while the person is still in hospital. A neuropsychologist helps to rebuild memory and attention and to work out ways round the gaps; a speech and language therapist works on speech and swallowing; a physiotherapist on movement and balance; an occupational therapist on independence in daily life. There is a separate task that is nearly always underestimated: supporting the family. Changes in a loved one's character are harder on relatives than physical weakness is, and they need help too.

What can be prevented

Encephalitis cannot be prevented outright, but several of the routes leading to it can be closed firmly.

• Childhood vaccines against measles, mumps and rubella also protect against the encephalitis those infections can cause. Timing and the number of doses differ between countries, so follow the local schedule.
• The tick-borne encephalitis vaccine makes sense for anyone living where the virus circulates or travelling there, particularly if woodland, hiking or outdoor work is involved.
• The Japanese encephalitis vaccine is advised before a prolonged stay in rural areas of the countries where the infection occurs.
• The rabies vaccine — beforehand for those who work with animals or travel to regions where rabies is present, and after a bite, for everyone and as fast as possible.
• Protection against bites. Covering clothing, repellents, checking the body over after being in the countryside, removing a tick properly, a mosquito net while travelling. Simple things that work.
• The chickenpox and shingles vaccines, where they are part of the programme, also lower the risk.

The reverse is worth holding in mind: encephalitis after a vaccine is a great rarity, while after the infections themselves it happens incomparably more often. This is one of those cases where the arithmetic in favour of vaccination is plain.

Online consultation

On this subject a remote appointment fits at two points, neither of them the acute one. Beforehand: working out whether vaccinations are needed for a trip, which ones and how far in advance to have them, what to do after a tick bite or an animal bite, how to judge the risk at a particular destination. And after discharge: the doctor goes through the hospital summaries, explains what the results mean, helps to build the recovery plan, reviews anticonvulsant treatment, the return to work and to driving, and support for memory and mood, and answers the questions of relatives, who usually find it hardest of all. It also serves when somebody is unsure whether to worry about a child's headache and temperature — the doctor will say which signs to watch for. The symptoms of encephalitis themselves, however, are not assessed on a screen: they mean calling an ambulance at once, and that is the only correct order of events.

This material is for information only and does not replace medical advice.